This invention relates to a programmed shutter and more particulary a device for adjusting a degree of displacement of the sector in the programmed shutter of a type for opening and closing a sector which is also used as an aperture vane.
In a conventional type of said programmed shutter described above, a degree of displacement of the sector is automatically adjusted by an exposure control mechanism, the degree of displacement of the sector is changed every time in response to a brightness of the object to be photographed, and both a diameter of the aperture and a shutter speed are simultaneously set.
In brief, in a conventional prior art which will be described hereinbelow, a cooperative relation between the light receiving device and the exposure meter during a first stroke will define a stopping position of an automatic exposure cooperative member, the sector is slightly opened by a predetermined stopper when the object to be photographed is light to perform a closing operation, and a position of the stopper is changed when the object to be photographed is dark and thereby a large aperture diameter and a long shutter speed may be obtained. A combination between the aperture and the shutter may be continuously selected at an intermediate value.
The prior art programmed shutter described above utilizes in general a system for adjusting a ratio of a lever for transmittance of movement from the driving member for use in opening and closing the sector to the sector operating member by an automatic exposure cooperative mechanism (so called variable magnification lever system). This conventional system has such disadvantages as described below which are not preferable for the system.
That is, it is required that a variable magnification lever having a center of rotation which is moved is arranged between the opening and closing driving member and the sector operating member, or that the center of rotation of the sector operating member is directly changed to use the sector operating member as the variable magnification lever. However, in either case, since a center of rotation of the member which will directly affect a degree of displacement of the sector is changed, it is difficult to eliminate an element which will cause an insufficient performance and an error will be made when the object to be photographed is particulary light and sometimes it is not possible to perform a preferable photographing.
In view of the above described disadvantages, the present invention will provide a programmed shutter for adjusting a degree of opening of the sector by changing only a degree of projection of the sector opening member, and in reference to the provision, the sector opening member is movably arranged on a moving driving member, a degree of projection of the sector opening member during displacement thereof is restricted by a control member which will be displaced in cooperation with automatic exposure sensor mechanism and a degree of displacement of the sector operating member is determined by the degree of projection.